Thermometer.



O. HERRMANN.

THERMOMETER.

APPLICATION FILED JUNE 1. 1914.

1,136,527., mmemr. 20, 1915.

mmwhmwmum Aphllcstion one 511m? 1, 18M. sens: rm.

lowing is a specification.

This invention relates to thermometers havlng their capillary tubes located n a groove in a. glass plate.

l Vcll-lmown gloss-plate or WlIldOW thermometers of the ordinary kind, in which the capillary tube providednl th the hulb is mounted on the graduated s1. of the glass plate, have considerable parallax on account of the fairly large diameter of the tube, so

that it is very diilicult to read the thermometer exactly. it the capillary tube contuining mercury is let into the glass plate without the base of the groove being polished, the thermometer can be read only from the enameled side in light shining through the plate. In incidental light the reading of the thermometer is possible not at all or only with diiiiculty, because on the enameled side of the glass the coating covers the scale, while on the smooth side the filament of mercury is covered by the rough surface of the groove. Therefore the means frequently employed with Wooden or motel scales, e. letting the tubes up to half their diameter into the graduated beseplute, is notsuituble for adoption in glass-plate thermometers which are to be read in incidental light and in light shining through from behind. 1

Forms of thermometers are also lmown in which the tube is mounted on the graduated side which is enameled with the exception of the narrow middle strip under the tube, the numerals being Written in mirror script or reversed Writing. These thermometers have a. smooth graduated plate Without a groove. The enamel cost covers only the greduations, and not the space under the mercury tube. Such an instrument can be read both from the enameled side or the other in light shining through the glass, but from the latter side only in incidental light. Ethos, however, considerable purellax because the mercury filament and the scale are not located in one plane. This is not the case in another known construe tion, in Which the graduated glass plate has a slot-like cut for receiving the tube. The cut is, however, unsuitable for technical moun on r flncclficstton or Letters intent.

of the liquid and t tnngulsr section. in sit the cause the diilicult end the o surt'sce is not con nous, .c sightly and dilljcult to cos. surface.

According to Irgroove in the rear of tprovideit with polished surface,

to scale, known manner on the rear oi tn being reed together through the gls The invention consists in the cons. arrangement coinhinz 'ion scribed her inafter sud pointeo clniins.

Several illustrative einhodirn invention represented b Wily pie in the accompanying droning, 1n:

Figures 1 and 9. are horisonini is showing two forms of my i momcter, and Figs. 3 to ii sections showing various mountiiuo the tube on the gloss Referring tirstiy to Fig. 1, mometer consisting the mounted on the graduated gloss the simplest form of groove 0 its tube is mounted, the encore being o:

hates the rear of glass ,1 "roridcd with the scale and c the trout sine which the thermometer read. The tom of the groove, 2'. e. face side a, is smooth and polished, sides may have any desired slthat the groove. has trnpezoi L in Fig. 2 the groove c has "'3 bottom curved inwerd, c. towers B. rlhen observing the tl. .Inorue the front the filament of iiqu' i greatly magnified transversely. n impairing the clistinctncss tube can sequently he made narrower and the smaller than is otherwise suitable. if lilo. base of the groove were curved in t e posite direction the eliect would. re verse.

Fig. 3 shows a thermom tube B attached in. the lino means of two clumps of, the s being located outside the s phi" Fig. 52 shows 21 similar thern'ionie that the cylindrical bulb if is if the glass plutennd is oi? o.

Y in the thermometer shown in Fi 5 the tube B and its bulb b are inclosed etween two glass plates A, each of which has a recess for the bulb as in the plate A in Fig. 4. In this form also the plane of the scale coincides with'the plane of contact of the "twoplates.

Thermometers of very various kinds can be made in the described manner including, for example, the two-limbed six thermometer. 1 Fig. 6 shows a specially advantageous form of thermometer. In this the graduated plate A is provided at the lower end of the groove with a large hole which tapers so much toward the rear of the plate that the bulb cannot pass through it. The tube B is inserted through the hole from the front, laid into its groove and attached above to the plate by one single clamp d. A second attachment is not necessary .be-

cause the bulb is supported in the said hole,

in the plate.

. I claim p 1. In a thermometer, the combination of a glass plate graduated on the rear side and a capillary tube having a bulb mounted thereon, said plate having a groove in the rear side thereof in which the tube is located,

the bottom of the groove being polished and curved toward the tube.

2. A thermometer comprising in combination two glass plates each having a groove OTTO HERRMANN.

Witnesses ALFRED HOFFMANN, Fnnn. BESKER. 

